@cute_otaku pretty sure his definition of fun is grinding levels, Anakastic personality disorder is often accompanied with Obsessive Compulsive Disorder. In this case it's getting stronger, soloing and breaking things. He shows all the signs of both so he can't help himself and to do otherwise would actually cause him discomfort
Btw the author isn't even being suddle about who he's going to make the FL with these drops lol. Not that I hate it, as mc being a necromancer doesn't really need much equipment, especially considering his defence and damage transfer skills